From Kiva's FAQ at:
http://www.kiva.org/about/faq/Will PayPal charge me to withdraw from my Kiva Account?No. When you request to withdraw funds from your Kiva Account, Kiva.org uses a PayPal function which charges the sender, not the recipient. Assuming 100% repayment, you will receive 100% of your money returned to you.
How do I pay if I don’t have a PayPal account?You can pay by credit card through PayPal’s website, even if you don’t have a PayPal account. You will, however, need a PayPal account when you withdraw your funds as Kiva.org uses PayPal to handle all financial transactions.
PayPal is not accepting my payment.Kiva.org does not have access to your PayPal account or your payment details through PayPal. This is all handled solely by PayPal. If you have trouble making your payment please contact the PayPal Customer Service line created by PayPal specifically for Kiva users at 888-445-5032 (Toll Free — US) or 402-952-8811 (International), Monday through Friday, 8 a.m. to 5 p.m. CST. These phone numbers are staffed by PayPal employees who are specially trained to help Kiva lenders!
PayPal Discussions on Kiva FriendsWithdrawing Kiva Credit Back To PayPalhttp://www.kivafriends.org/index.php/topic,914.0.htmlHighlights: Withdrawing your Kiva Credit is currently done manually by Kiva and can take 1-3 weeks, depending on volume, before your credit becomes cash in your PayPal account.
Transferring money from your PayPal account to your bank accounthttp://www.kivafriends.org/index.php/topic,543.0.htmlHighlights: PayPal offers many options to convert your balance to cash. The most common being direct deposit into a specified bank account. PayPal requires that you verify your bank account first, usually by depositing a random amount of change after you enter your routing and account numbers. When the amount appears on your transactions, you enter on PayPal's site and verify your account.
Search Kiva Friends for more PayPal related discussions
PayPal
http://www.paypal.comPayPal Help Center
https://www.paypal.com/cgi-bin/helpweb?cmd=_help